The present invention pertains generally to a restraint system with an adjustable airbag.
The following discussion pertaining to the implementation of the invention is intended to assist the reader in understanding the advantages of the invention and is not to be interpreted as presenting the state of the art for this invention.
To ensure the safety of passengers in land vehicles, aircraft, and watercraft, restraint systems suitable to each case are installed. A combination of a safety belt and an airbag is used to minimize the consequences of an accident. Whereas the safety belt holds the vehicle occupant securely in his seat, the inflated airbag cushions his impact against parts of the vehicle. These devices in their totality significantly decrease the forces of deceleration which act on the vehicle occupants when an accident occurs. The injuries which might result from an accident are therefore reduced or possibly even prevented entirely.
Whereas the safety belt reduces the acceleration of the torso during a collision of the vehicle, the extremities and especially the head are still subject to initial acceleration and deflection. To reduce the deflection of the head and to cushion its impact in closed vehicles, head airbags are used, which are installed in the area of the door, the pillar, or the roof. So that the airbag, when in its original position, will be as close as possible to the body areas of the occupants to be protected, systems are already known which mount the airbag on the safety belt.
U.S. Pat. No. 5,288,104 discloses to this end a cushioning safety device for use in a vehicle, which is suitable for mounting on a safety belt. For this purpose, a tube-like container is provided with hook portions at its ends, by which it can be fastened to a safety belt in the area of the occupant's chest. The container contains a folded airbag, which can be expanded through a valve in the container. An elastic tube connects the airbag to an inflation unit installed in the vehicle. The inflation unit contains not only an accident detection sensor but also a gas generator, which inflates the airbag through the elastic tube.
The safety device created in this way can be installed as standard solution in any vehicle with an integrated safety belt, either at the factory or as a retrofit. Because the elongated container is connected to the safety belt via the hook portions, the container can be shifted lengthwise along the belt and its position thus adapted to the vehicle occupant in question. The proposed ability to shift the position of the airbag increases comfort and the adaptability to individual circumstances.
Nevertheless, the possibility of being able to shift the position of the airbag can lead during an accident to an uncontrolled displacement of the airbag as it is being deployed, which can have devastating results for the vehicle's occupants under certain conditions. Against this background, it can be seen that the proposed design offers room for safety-relevant improvements.
It would thus be desirable and advantageous to make available an improved restraint system with an airbag mounted relocatably on a belt, namely, a restraint system which avoids the shortcomings of the state of the art and which, during an accident, makes it possible for the airbag to remain in its proper position as it is being deployed.
According to one aspect of the invention, a restraint system for an occupant of a vehicle comprises a belt; an airbag unit arranged on the belt, wherein the positions of the belt and the airbag unit can be shifted with respect to each other; an airbag in the airbag unit; and means by which the airbag can be secured on the belt, i.e., means by which the airbag and the belt can be fastened together upon deployment of the airbag without the possibility of a shift in their relative positions.
The present invention solves the problems arising from the state of the art by providing the position-securing means. These means make it possible to connect the airbag and/or the airbag unit to the belt so that they cannot shift their positions. Thus, under normal conditions, the airbag unit and the belt can be easily relocated with respect to each other, so that the device can be adapted individually to the occupant in question. At the same time, it is guaranteed that the airbag, when deployed, will be held securely in its position on the belt.
Overall, a restraint system for the occupants of land vehicles, watercraft, or aircraft is created which can be adapted individually to any circumstances and requirements and which offers not only flexibility and comfort but also a maximum of safety.
According to another advantageous feature of the present invention, the position-securing means are surrounded by a cover. In addition to protecting the position-securing means from, for example, undesirable mechanical effects or dirt, which could impair the functioning of the device or even destroy it, it is ensured in this way that the position-securing means remain inactive until the cover is removed.
According to another advantageous feature of the present invention, the cover is attached to the airbag unit and can be moved out of the way by the deploying airbag. The attachment of the cover to the airbag unit in combination with the movement of the airbag as it is being deployed means that no additional actuators are necessary to move the cover out of the way. The deploying airbag itself therefore serves as the direct actuator which removes the cover, as a result of which the position-securing means are activated.
According to another advantageous feature of the present invention, the position-securing means are designed advantageously according to the principle of a hook-and-loop fastening. For this purpose, a first part of the hook-and-loop fastening is provided on the belt, whereas a second part of the hook-and-loop fastening is provided on the airbag unit, so that it can enter into a hook-and-loop connection with the first part.
The advantages of a hook-and-loop fastening are to be found in its high resistance to aging and deformation. Such fastenings are also low in weight and can be processed easily together with the fabrics and textiles predominantly used in these types of restraint systems. Their functionality is ensured even after becoming wet and, depending on how they are made, even at high temperatures.
When certain requirements are to be met, however, it is also possible in principle to use other types of positive, nonpositive, or bonded fastenings which meet the requirement of secure fixation. For example, adhesive surfaces or anti-slip surface structures which are provided on the belt and/or on the airbag unit are also conceivable.
According to another advantageous feature of the present invention, the undeployed airbag in the folded state is at least partially surrounded by the cover. The cover thus wraps completely or at least partially around the folded airbag, wherein the cover is arranged in a U-like fashion around the folded airbag.
As a result, the cover is pushed out of its original position by the airbag as it expands during its deployment. Because the cover is attached to the airbag unit, a specific area of the cover not connected to the airbag unit is pulled very quickly out of its original position and thus moved out of the way of the position-securing means, as a result of which they are activated. For this purpose the cover preferably has a flat and readily flexible structure.
Not only metal or plastic strips but also foils as well as, for example, fabrics, textiles, or leather can be used for the cover. Combinations of the materials mentioned above are also feasible.
According to another advantageous feature of the present invention, the cover is preferably arranged as a sliding layer between the first part of the hook-and-loop fastening and the second part of the hook-and-loop fastening. The two parts of the hook-and-loop fastening, which adhere to each other on direct contact, are thus isolated from each other and can move relative to each other. Arranging the first part of the hook-and-loop fastening on the belt, therefore, makes it possible for the airbag unit and the belt to be relocated easily with respect to each other.
According to another advantageous feature of the present invention, the airbag unit comprises at least one flap arranged on it, wherein the flap extends around at least part of the periphery of the belt.
The flap serves as a movable connection between the airbag unit and the belt. To accomplish this, the flap wraps around the belt and thus makes it possible for the airbag unit and the belt to be relocated relative to each other. The flap can also designed in the form of a tunnel for this purpose, in which case it can extend over the entire length of the airbag unit.
It is also possible in this way to construct a closed system, which can be guided over the entire length of the belt, and which is also protected from the intrusion of foreign bodies.
According to another advantageous feature of the present invention, an especially compact design can be achieved by providing the airbag unit with a gas generator. The complicated task of installing a gas supply line proceeding from an external gas source is thus eliminated.
The gas generator integrated into the airbag unit is in working connection with an accident-detecting sensor system. When the sensor system is triggered, a control signal is produced. A control unit then activates the gas generator, as a result of which the gas is conducted into the airbag through an appropriately designed gas-conducting connection. The sensor system required for this purpose is connected directly or indirectly to the gas generator by a signal line.
There are in principle, however, other possible ways of transmitting the signal for deploying the airbag, such as optical or wireless connections. In general, for the sake of an especially compact design, the necessary sensor system can also be integrated directly into the airbag unit.
According to another advantageous feature of the present invention, the airbag is located near the neck of the occupant. Because of its individually adjustable proximity to the head area, the restraint system described here provides the head with especially effective protection. Especially when deployed on four-point or five-point belts, the airbag unit can have a shape which extends around the back and side areas of the neck, which guarantees, for example, that the head will be supported on three sides.
According to another advantageous feature of the present invention, in a variant of the restraint system the airbag unit is connected to the seat. When the airbag is arranged near the occupant's neck, the airbag unit will be connected to the seat by way of the seat back.
According to another advantageous feature of the present invention, the airbag unit is connected to the headrest of the seat, and the headrest comprises a gas generator. As a result, a very compact design is obtained, which allows the rapid and easy replacement of the airbag unit. A deployed airbag unit can therefore be replaced in a very short time simply by replacing the headrest equipped in this way. Even vehicles without an airbag unit can be retrofitted simply by replacing the headrest.
According to another advantageous feature of the present invention, the headrest comprises an impact airbag. The particular advantage here is attributable to the combined effect of the impact airbag and the airbag unit. In cases where both the airbag unit and the impact airbag are deployed, the head area of the occupant will be almost completely enclosed and thus protected. The severity of accident scenarios in which the energy of the impact causes the vehicle to accelerate forward and the head to snap backward can be minimized with the help of the impact airbag. The typical forward acceleration of the head after a front-end collision, followed by the backward acceleration of the head, is also reduced by the airbag unit in combination with the impact airbag.
In conjunction with a belt retractor or possibly a manual length adjuster, the belt can be adjusted in the lengthwise direction with respect to the airbag unit.
According to the present invention, a restraint system for occupants of a vehicle is created, which, in spite of the fact that it can be adjusted by relocating its components with respect to each other, ensures that deploying airbag will be secured in its proper location as required for safety. It thus offers a maximum of comfort and safety, and at the same time it can be adjusted individually to each occupant of the vehicle.
Thanks to the position-securing means, which hold the airbag securely in place, even an unexpected foreign body in the area into which the airbag expands and with which the inflated airbag could collide cannot shift the airbag out of position at the moment of its deployment.
In this connection, we can also see the advantages of the invention over an airbag system which is installed directly in the structure of the vehicle and which, when deployed, can be ineffective or even hazardous in some cases if the occupant is in an unexpected position or has assumed an unexpected posture. In addition, proper selection of the individual components guarantees maintenance-free operation without the problems associated with aging.
Because the restraint system described here functions independently of the form and function of the interior of the vehicle surrounding the seat, the occupants of any type of vehicle can be protected. With the system presented here, it is also possible to equip all of the seats in vehicles for transporting passengers such as busses, trains, and airplanes. If belts are already present, these can be easily retrofitted. It is also possible in particular to protect the occupants of aircraft, such as the pilots, in a simple and effective manner.